Chapter 7 Flashcards
What is selective permeability and what is it exhibited by?
Exhibited by the plasma membrane, allowing certain substances to pass through
Ampipathic molecules
Molecules that possess both a hydrophobic and hydrophilic molecules
What is the fluid mosaic model?
A model that displays the phospholipid bilayer as a mosaic of protein molecules bobbing on the bilayer
Where is Steroid cholesterol found, and what does it do?
Wedged between phospholipid molecules in the plasma membrane of animal cells, with temperature affecting its fluidity
How does temperature affect steroid cholesterol?
At high temperatures, it makes the membranes less fluid
What are integral proteins?
Proteins that penetrate the hydrophobic interior of the lipid bilayer. Majority are transmembrane proteins
Peripheral proteins
Appendages loosely bound to the surface of the membrane, often bound to the integral proteins
What are the types of proteins on a plasma membrane? (6)
Transport
Enzymatic
Signal transduction
Cell to cell recognition
Intercellular joining
Attachment to the cytoskeleton and Extracellular matrix
What are Transport proteins (4)
Spans the membrane and provides a hydrophilic channels across the membrane that is selective for a particular solute.
Some shuttle a substance by changing shape
Some use ATP actively pump substances
Hydrophilic
Enzymatic proteins (2)
Enzymes with active site exposed to substances in the adjacent solution
Can form teams of enzymes with active to carry sequential steps of a metabolic pathway
Signal transduction proteins (2)
Proteins with binding sit with a specific shape that fits the shape of chemical messengers like hormones
Messengers can change the shape of protein to relax the message
Cell to cell recognition proteins
Serves as ID tags recognized by membrane proteins of other cells
Intercellular joining proteins
Membrane proteins of adjacent cells hook together to form junctions
Protein attachments to the cytoskeleton and Extracellular matrix
Binds to said substances to maintain cell shape, and stabilize location of certain membranes
What are glycolipids?
Carbohydrates bound to lipids for cell to cell recognition
Glycoproteins
Carbohydrates bonded to proteins
What passes the phospholipids easily?
Hydrophobic/ Nonpolar molecules
What are aquaporins?
A transport protein for water
What are carrier proteins?
Proteins that hold onto molecules or ions and change shape in a way to transport said molecules
What is diffusion?
Movement of particles of substances
Dynamic equilibrium
Solute molecules continue to cross a membrane at equal rates in both directions
What is tonicity and what does it depend on? (2)
Ability of a surrounding solution to cause a cell to gain or lose water
Depends on its concentration of solutes that cannot cross the membrane relative to that inside the cell
What is an isotonic environment?
Equal amounts of nonpenetrating solutes in and outside the cell
No net movement
Hypertonic (2)
More nonpenetrating solutes surrounding the cell
Cells lose water, shrivels, and dies
Hypotonic
Less nonpenetrating solutes surrounding the cell
Cell takes too much water, swells, and lyse
What is osmoregulation, and what organisms use it?
Control of solute concentrations and water balance
Used with organisms without a rigid cell walls to survive hypertonic and hypotonic environments
What environment are organisms with cell walls in?
Hypotonic environment
Turgid pressure
When a cel wall expands to its max capacity due to water intake, eating back pressure on the cell
Turgid cell (2)
When a cell wall is firm
The healthiest state for plant cellsb
Flaccid state (2)
When a cell with a cell wall is in an isotonic environment
No water entering the cell, making it limp
Plasmolysis (2)
When a plant with a cell wall is in a hypertonic environment
Loses water, shrivels, and membranes pull away from the cell wall
Facilitated diffusion
Passive diffusion with the help of transport proteins
Gated channels
Ion channels that open or close in response to stimuli like electrical
ATP and active transport (2)
ATP transfers it’s terminal phosphate group directly to the transport protein
Protein changes shape so that a molecule can bind to it
Sodium potassium pump (2)
Pumps three sodium out and 2 potassium in to maintain a high potassium concentration and lower sodium concentration in the cell
Maintains a negative charge
Voltage (2)
Electrical potential energy/ separation of opposite charge
Cytoplasmic side is negative in charge
Membrane potential
Voltage across a membrane
Ranges from -50 to -200 millivolts
Acts as a battery to provide an energy source that affects transport
Favors passive transport of cations into the cell
Electrochemical gradient (3)
Two forces driving the diffusion of ions across the membrane
The two forces include a chemical and electrical force
Active transport may be necessary when electrical force is oppose the concentration
Electrogenic pump
A transport protein that generates voltage across a membrane
Proton pump and where is it found?
A protein that actively transports protons out of the cell
Found in plants, fungi, bacteria
What is Cotransport?
A transport protein, coupling, passive diffusion, followed by an active diffusion
Exocytosis
Secretion of certain molecules by the fusion of vesicles with the plasma membrane
Endocytosis (3)
Celtics in molecules and a particulate matter by forming new vesicles from the plasma membrane
A small area of the membrane sinks inward to form a pocket
The pocket than deepens punches and forms a vesicle
Ligand
Any molecule that binds specifically to a receptor site on another molecule
Phagocytosis
A cell engulfing, a particle by extending psuedopodia around it, and packages it within a food vacuole
And then they just after the vacuole fuses with a lysosome
Pinocytosis
I saw gulps and fluids into vesicles formed by infolding of a plasma membrane
Nonspecific
Receptor mediated Endocytosis
Type of Pinocytosis to acquire, book quantity of a specific substance
